Vibration generator moving vibrator by magnetic field generated by coil and holder used in vibration-generator

ABSTRACT

A holder is used while attached to a chassis of a vibration generator that moves a vibrator to generate a vibration. The holder includes a vibrator retention unit retaining the vibrator, a fixed unit fixed to the chassis, and an arm. The arm connects the fixed unit and the vibrator retention unit, and the arm supports the vibrator retention unit while the vibrator retention unit can be displaced with respect to the fixed unit. The fixed unit, the arm, and the vibrator retention unit are integrally formed using resin.

This application is a divisional of U.S. application Ser. No. 13/618,987filed Sep. 14, 2012, which is based on and claims priority under 35U.S.C. 119 from Japanese Patent Application No. 2011-207335, No.2012-028847, No. 2012-028848, No. 2012-130712, and No. 2012-130758 filedwith the Japan Patent Office on Sep. 22, 2011, Feb. 13, 2012, Feb. 13,2012, Jun. 8, 2012, and Jun. 8, 2012 respectively, the entire content ofwhich is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a holder and a vibration generator,particularly to a holder, which is used in a vibration generator thatmoves a vibrator to generate a vibration by passage of a current througha coil, and the vibration generator.

Description of the Related Art

Various vibration generators having a structure, in which a vibratorincluding a magnet is supported by a chassis with a spring unitinterposed therebetween, are used as the vibration generator that movesthe vibrator to generate the vibration. This kind of vibration generatorincludes a coil, which is disposed below a magnet while being oppositethe magnet. When a current is passed through the coil to generate amagnetic field, the vibrator moves while deforming a spring unit.

For example, Document 1 discloses a vibration generator having astructure in which a vibration unit having the magnet is supported usinga plate spring. In the vibration generator, one plate-like coil isdisposed opposite the magnet of the vibration unit. One end of the platespring is fixed to a chassis with a screw. The other end of the platespring is fixed to a weight of the vibration unit by caulking.

Document 2 discloses a vibration generating device, in which the magnetis attached to a movable block and the coil is wound around a rod-shapedyoke body disposed along the magnet. In the vibration generating device,the spring unit supporting the movable block and a frame are integrallymolded using a resin material.

-   [Document 1] Japanese Patent Laying-Open No. 2003-24871-   [Document 2] Japanese Patent Laying-Open No. 2010-94567

In the vibration generator disclosed in Document 1, the vibrator issupported using the plate spring attached to the chassis. Therefore, astructure of a portion in which the plate spring is attached onto thechassis side becomes complicated. Specifically, in the vibrationgenerator disclosed in Document 1, the plate spring is attached to thechassis with the screw. Therefore, an assembly man-hour of the vibrationgenerator increases, and the number of components also increases, whichincreases a production cost of the vibration generator.

The problem becomes more prominent with increasing demand for downsizingand a low profile of the vibration generator. That is, because thedownsizing of the component advances with the downsizing of thevibration generator, it is necessary to adopt attachment methods, suchas spot welding, instead of screw clamp or caulking, and the structureof the attachment portion between the components becomes complicated.For example, in the case that the spot welding is performed to theattachment portion of the plate spring and the chassis, it is necessaryto perform the spot welding at many points in order to maintain highreliability of the vibration generator, and sometimes it takes a lot oftrouble with the production. This is because a region where the spotwelding is performed is relatively brittle against an impact force.

The vibration generating device disclosed in Document 2 has thestructure in which the spring unit and the frame are integrally molded,and the problem with the method for joining the spring unit and thechassis is not originally generated. However, in this case,unfortunately the material used for the chassis is restricted to amaterial, which can be molded while being integral with the spring unit.

An object of the present invention is to provide a holder, which is usedin the high-impact-resistance, easily constructible, andlow-production-cost vibration generator, and the vibration generator.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a holder, whichis used while attached to a chassis of a vibration generator that movesa vibrator to generate a vibration, includes: a vibrator retention unitretaining the vibrator, a fixed unit being fixed to the chassis; and anarm connecting the fixed unit and the vibrator retention unit, the armsupporting the vibrator retention unit while the vibrator retention unitcan be displaced with respect to the fixed unit, wherein the fixed unit,the arm, and the vibrator retention unit are integrally molded usingresin.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a vibration generator according to afirst embodiment of the present invention.

FIG. 2 is a sectional view take on a line A-A of FIG. 1.

FIG. 3 is a perspective view illustrating a holder.

FIG. 4 is a sectional view of a frame taken on a line B-B of FIG. 1.

FIG. 5 is a sectional view of the frame taken on a line C-C of FIG. 4.

FIG. 6 is a sectional view of a yoke taken on the line B-B of FIG. 1.

FIG. 7 is a plan view illustrating a vibration generator according to asecond embodiment.

FIG. 8 is a sectional view taken on a line E-B of FIG. 7.

FIG. 9 is a perspective view illustrating a holder.

FIG. 10 is a plan view illustrating the holder.

FIG. 11 is a development diagram illustrating a board.

FIG. 12 is a plan view illustrating a yoke.

FIG. 13 is a sectional view taken on a line F-F of FIG. 12.

FIG. 14 is a plan view illustrating a vibration generator according to athird embodiment.

FIG. 15 is a sectional view taken on a line G-G of FIG. 14.

FIG. 16 is a perspective view illustrating a holder and a vibrator.

FIG. 17 is an exploded perspective view of the holder and the vibratorof FIG. 16.

FIG. 18 is a development diagram illustrating a board.

FIG. 19 is a plan view illustrating a yoke.

FIG. 20 is a sectional view taken on a line H-H of FIG. 19.

FIG. 21 is a plan view illustrating a vibration generator according to afourth embodiment.

FIG. 22 is a sectional view taken on a line J-J of FIG. 21.

FIG. 23 is a plan view illustrating a holder of the fourth embodiment.

FIG. 24 is a bottom view illustrating a frame of the fourth embodiment.

FIG. 25 is a sectional view taken on a line K-K of FIG. 24.

FIG. 26 is a bottom view illustrating a frame used in a vibrationgenerator according to a first modification of the fourth embodiment.

FIG. 27 is a side view of the flame.

FIG. 28 is a sectional view taken on a line L-L of FIG. 26.

FIG. 29 is a side sectional view illustrating a configuration of avibration generator according to a second modification of the fourthembodiment.

FIG. 30 is a side sectional view illustrating a frame used in avibration generator according to a third modification of the fourthembodiment.

FIG. 31 is a plan view illustrating a configuration of a vibrationgenerator according to a fourth modification of the fourth embodiment.

FIG. 32 is a side sectional view of the vibration generator of thefourth modification.

FIG. 33 is a bottom view of the vibration generator of the fourthmodification.

FIG. 34 is a view illustrating a configuration of a holder in thevibration generator of the fourth modification.

FIG. 35 is a plan view illustrating a vibration generator according to afifth embodiment.

FIG. 36 is an exploded perspective view illustrating a holder and avibrator of the vibration generator.

FIG. 37 is a plan view illustrating a vibration generator according to afirst modification of the fifth embodiment.

FIG. 38 is a perspective view illustrating a holder and a vibrator ofthe vibration generator.

FIG. 39 is an exploded perspective view illustrating the holder and thevibrator.

FIG. 40 is an enlarged view illustrating a portion in which areinforcing plate of the holder is disposed.

FIG. 41 is a side view of the holder.

FIG. 42 is a plan view illustrating a holder of a vibration generatoraccording to a second modification of the fifth embodiment.

FIG. 43 is a sectional view taken on a line M-M of FIG. 42.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a vibration generator using a holder according to anexemplary embodiment of the present invention will be described withreference to the drawings.

A vibration generator has a structure in which a vibrator retaining amagnet is supported by a chassis while being able to be displaced withrespect to the chassis. A coil is disposed near the vibrator. Thevibrator generates a magnetic field in order to change at least one of aposition and an attitude with respect to the chassis. The vibrationgenerator is what is called a linear type vibration generator thatgenerates a vibration force by reciprocating the vibrator in response toexcitation of the coil.

First Embodiment

FIG. 1 is a plan view illustrating a vibration generator according to afirst embodiment of the present invention. FIG. 2 is a sectional viewtaken on a line A-A of FIG. 1.

In FIG. 1, a holder 50 and the like, which are originally hidden behindan upper surface of a frame 20, are partially illustrated by a solidline for the purpose of easy understanding of a component layout in avibration generator 1.

In the following description, with respect to vibration generator 1,sometimes an X-axis direction of an coordinate in FIG. 1 is referred toas a crosswise direction (a positive direction of an X-axis is a rightdirection when viewed from an origin), and a Y-axis direction isreferred to as a front-back direction (a positive direction of a Y-axisis backward when viewed from the origin). Sometimes a Z-axis direction(direction perpendicular to an XY-plane in FIG. 1) in FIG. 2 is referredto as a vertical direction (a positive direction of a Z-axis is upwardwhen viewed from the origin).

[Entire Structure of Vibration Generator 1]

As illustrated in FIG. 1, vibration generator 1 includes a double-sideboard (an example of the circuit board) 10, frame (an example of thechassis) 20, a bottom plate 30, a coil 40, and holder 50. In the firstembodiment, holder 50 includes four columnar bodies (an example of thefixed unit) 51 (51 a, 51 b, 51 e, and 51 d), four arms 53 (53 a, 53 b,53 c, and 53 d), and one vibrator retention unit (hereinafter sometimessimply referred to as retention unit) 55. A vibrator 80 including amagnet 60 and a yoke 70 is retained in retention unit 55.

Vibration generator 1 is formed into a low-profile,substantially-rectangular-solid shape, in which a vertical size isrelatively small, as a whole. For example, in vibration generator 1,external dimensions in the crosswise direction and the front-backdirection range from about 10 millimeters to about 20 millimeters.Vibration generator 1 has a box-shaped external form, in which sidesurfaces in all directions and an upper surface are constructed by frame20 and a bottom surface is covered with double-side board 10.

In the first embodiment, frame 20 and yoke 70 are made of soft magneticmaterials, such as iron.

Double-side board 10 is a printed wiring board in which patterns areprovided in double sides. Two terminals 11 and 123 are provided in acentral portion on the upper surface of double-side board 10. Terminals11 and 12 are electrically connected to a pattern (not illustrated)provided on the bottom surface of double-side board 10. Winding endportions of coil 40 are connected to terminals 11 and 12 by soldering,and coil 40 can be energized through the pattern on the bottom surfaceof double-side board 10. A method for connecting the winding endportions of coil 40 is not limited to the soldering, but terminals 11and 12 and the winding end portions of coil 40 may be connected bytechniques, such as resistance welding and laser welding.

Bottom plate 30 is formed into a rectangular plate shape so as to coverthe substantially whole upper surface of double-side board 10. Forexample, bottom plate 30 and double-side board 10 are fixed to eachother with an adhesive sheet or a bonding agent interposed therebetween.In other words, double-side board 10 is connected along bottom plate 30.An opening 31 is provided in the central portion of bottom plate 30 suchthat terminals 11 and 12 are exposed upward. Four joining units 33 (33a, 33 b, 33 c, and 33 d) are formed in four sides of bottom plate 30. Asillustrated in FIG. 2, each joining unit 33 is bent upward atsubstantial 90 degrees from bottom plate 30. A section of each joiningunit 33 has an L-shape together with a region on double-side board 10 ofbottom plate 30. Each joining unit 33 is formed such that an outsidesurface of joining unit 33 contacts an inner surface of a side portionof frame 20. Bottom plate 30 is disposed further away from coil 40 withrespect to vibrator 80. That is, bottom plate 30 and frame 20 coversvibrator 80 and coil 40.

In the first embodiment, bottom plate 30 is made of a nonmagneticmaterial Bottom plate 30 is made of nonmagnetic metallic materials suchas nonmagnetic stainless steel. Bottom plate 30 is not limited to themetallic material, but bottom plate 30 may be made of resin.

Frame 20 has a rectangular-solid shape, in which the bottom surface isopened, as a whole. For example, frame 20 is formed by drawing a steelplate. Corner portions (region between the side surfaces) of frame 20are connected with an R-surface portion Interposed therebetween whenviewed from above. As illustrated in FIG. 2, frame 20 is disposed so asto cover the upper surface of double-side board 10 from above ofdouble-side board 10. Frame 20 is fixed to bottom plate 30 such that theinner surface of the side surface is connected to joining unit 33 bybonding or welding while contacting the side surface of joining unit 33of bottom plate 30. In other words, bottom plate 30 is attached to frame20. Frame 20 may be fixed to bottom plate 30 by fitting flame 20 injoining unit 33 or by another method.

Thus, because vibration generator 1 has the structure surrounded byframe 20, vibration generator 1 is hardly acted by the surroundingmagnetic field. A magnetic flux of vibration generator 1 hardly leaks tothe outside, and the magnetic flux is prevented from affecting anexternal device or circuit.

Because vibration generator 1 is surrounded into a box shape by frame 20and bottom plate 30, a stiffness of vibration generator 1 is enhanced.Accordingly, vibration generator 1 can surely generate the vibration.Vibration generator 1 is easily attached to the external device.

Coil 40 has an elliptical, planar shape as a whole, and coil 40 is anair core coil around which a conductive wire is wound. That is, coil 40is a low-profile coil in which a size in a winding axis direction issmaller than that in a direction orthogonal to the winding axisdirection. Coil 40 may be constructed by slicing wound metallic foil orby laminating a sheet coil. Coil 40 may have a circular shape orpolygonal shapes, such as a quadrangular shape, when viewed from above.

As illustrated in FIG. 2, coil 40 is disposed on the upper surface ofbottom plate 30 such that the winding axis direction of coil 40 becomesthe vertical direction. As illustrated in FIG. 1, when viewed fromabove, coil 40 is disposed in the central portion of vibration generator1 while the surface of coil 40 is opposite the surface of vibrator 80.Coil 40 and bottom plate 30 are electrically insulated from each other.The two winding end portions of coil 40 are arrayed from the inside ofcoil 40 onto the upper surface side of double-side board 10 throughopening 31, and connected to terminals 11 and 12.

Holder 50, magnet 60, and yoke 70 are integrally molded by insertmolding. That is, holder 50 and vibrator 80 are integrally molded. Inthe first embodiment, pillar body 51, arm 53, and retention unit 55 areintegrally molded using an elastic material (an example of the resin).For example, heat-resistant fluorine rubber or silicon rubber can beused as the elastic material. Holder 50 is made of the rubber, whichallows a heat resistance property of vibration generator 1 to beenhanced. The elastic material is not limited to the rubber, but variousmaterials may be used as the elastic material.

[Structures of Holder 50 and Vibrator 80]

FIG. 3 is a perspective view illustrating holder 50.

In the first embodiment, holder 50 and vibrator 80, which includesmagnet 60 and yoke 70, are integrally molded. For the sake ofconvenience, holder 50 is illustrated in FIG. 3 while magnet 60 and yoke70 are not attached to retention unit 55. In other words, vibrator 80 isnot illustrated in FIG. 3, but only holder 50 made of the elasticmaterial is illustrated.

Each pillar body 51 has a columnar shape in which a height direction isthe vertical direction. A height of each pillar body 51 is less than asize in the vertical direction of the inside of frame 20.

As illustrated in FIG. 1, four columnar bodies 51 are disposed at fourcorners of holder 50 when viewed from above. Each pillar body 51 isdisposed in the R-surface portion of the side surface of frame 20.

As illustrated in FIGS. 1 and 2, vibrator 80 has a plate shape parallelto the horizontal plane (an XY-plane in FIG. 1). Vibrator 80 is formedinto a substantially rectangular shape, in which each side is parallelto the front-back direction or the crosswise direction, when viewed fromabove.

As illustrated in FIG. 1, vibrator 80 is disposed in the central portionof holder 50, namely the central portion of vibration generator 1 whenviewed from above. As illustrated in FIG. 2, vibrator 80 is disposed insubstantially parallel to coil 40 while the surface of vibrator 80 isopposite the surface of coil 40.

Magnet 60 is a low-profile permanent magnet having a rectangular-solidshape. For example, magnet 60 is magnetized into two poles in abottom-side portion opposite coil 40 such that an N-pole and an S-poleare divided in the front-beck direction. Yoke 70 is a rectangularmagnetic plate, which is attached so as to cover the upper surface ofmagnet 60, when viewed from above. The upper surface of yoke 70 isdisposed opposite the inner surface of the upper surface of frame 20.Yoke 70 includes ears 71 and 72 that project partially from the sides ofthe right and left toward the crosswise direction. For example, yoke 70and magnet 60 are bonded to each other by the spot welding or bondingthereby constituting integral vibrator 80. Vibrator 80, which includesyoke 70 and magnet 60, and holder 50 are integrally molded by the insertmolding while yoke 70 and magnet 60 are bonded. Projections 75 a and 75b are provided in the upper surface of yoke 70.

As illustrated in FIG. 3, retention unit 55 has a square-frame shape,which forms a substantially square aperture 55 a in which vibrator 80 isdisposed. In retention unit 55, two overhangs 55 b and 55 c are formedso as to overhang in the crosswise direction. As illustrated in FIG. 2,yoke 70 is disposed together with magnet 60 such that ears 71 and 72 areburied in overhangs 55 b and 55 c. Therefore, vibrator 80 is configuredto hardly drop out from retention unit 55.

Each of four arms 53 is formed so as to connect the corner portion ofretention unit 55 and pillar body 51 closest to the corner portion. Eacharm 53 is formed into a beam shape that extends in the crosswisedirection. As illustrated in FIG. 2, a size in a width direction(front-back direction) of arm 53 is smaller than that in a longitudinaldirection (vertical direction). Because each arm 53 is made of theelastic material, arm 53 is easily bent in the front-back direction. Therelationship between the sizes in the width direction and thelongitudinal direction of arm 53 is not limited to the example in FIG.2. The size in the width direction of arm 53 may be equal to that in thelongitudinal direction, or greater than that in the longitudinaldirection.

Each of four arms 53 is formed so as to be easily bent in the front-backdirection, so that vibrator 80 can mainly be displaced in the front-beckdirection with respect to pillar body 51. That is, vibrator 80 issupported by arm 53 so as to be able to be displaced in a directionsubstantially parallel to the horizontal plane.

Four columnar bodies 51 of holder 50 are fixed to frame 20, wherebyholder 50 is attached to flame 20. Therefore, the basic structure ofvibration generator 1 is formed such that vibrator 80 is supported byholder 50, which is integrally molded separately from frame 20, whilebeing able to be displaced with respect to frame 20.

In vibration generator 1, coil 40 generates the magnetic field in orderto reciprocate vibrator 80 with respect to frame 20. That is, when thecurrent is passed through coil 40, coil 40 is excited to generate themagnetic field in the vertical direction. When the magnetic field isgenerated, magnet 60 is affected by the magnetic field to generaterepulsive and attractive forces. A force displacing vibrator 80 forwardor backward according to the direction of the magnetic field and thedispositions of the magnetic poles of magnet 60 is affected to vibrator80. Therefore, vibrator 80 is displaced in the front-back directionwhile banding each arm 53. When viewed from above, vibrator 80 performslinearly reciprocating movement with respect to frame 20 by passing analternating current through coil 40. Therefore, vibration generator 1generates a vibration force.

When the alternating current decreases to weaken or eliminate themagnetic field, vibrator 80 returns to the central portion of vibrationgenerator 1 by a restoring force of arm 53 when viewed from above. Atthis point, because arm 53 is made of the elastic material, energyconsumed by arm 53 becomes relatively large. Accordingly, the vibrationis quickly damped.

In the first embodiment, because bottom plate 30 is made of thenonmagnetic material, a magnetic attractive force is not generatedbetween vibrator 80 and bottom plate 30. Vibrator 80 is smoothly andefficiently displaced according to the magnetic field generated by coil40. Accordingly, vibration generator 1 can be thinner and properlyoperated.

[Attachment Structure of Holder 50 to Frame 20]

In the first embodiment, pillar body 51 engages an engaging unit 21 (21a, 21 b, 21 c, and 21 d) provided in frame 20, thereby attaching pillarbody 51 to frame 20. Therefore, holder 50 is configured to be able to beeasily attached to frame 20.

FIG. 4 is a sectional view of frame 20 taken on a line B-B of FIG. 1.FIG. 5 is a sectional view of frame 20 taken on a line C-C of FIG. 4.

In the first embodiment, as illustrated in FIG. 5, engaging units 21 areprovided in the corner portions of fame 20 when viewed from above. Eachof four engaging units 21 includes two claws 22 and 23, namely, a firstclaw 22 (22 a, 22 b, 22 c, and 22 d) and a second claw 23 (23 a, 23 b,23 c, and 23 d).

As illustrated in FIG. 4, a U-shape notch is partially provided in theside surface of frame 20, and an interior portion of the notch ispressed into the inside of frame 20, thereby forming each of claws 22and 23 of engaging unit 21. Accordingly, claws 22 and 23 and frame 20are integrally molded. Each of claws 22 and 23 is formed in the abovemanner to partially provide a gap 25 (25 a, 25 b, 25 c, and 25 d) in theside surface of frame 20.

In the first embodiment, claws 22 and 23 are formed into the shapecorresponding to the shape of pillar body 51. That is, because pillarbody 51 has the columnar shape, claws 22 and 23 are formed into theshape along a side circumferential surface of pillar body 51. Asillustrated in FIG. 5, when viewed from above, each engaging unit 21 isformed such that at least a semicircle of the outer circumferencesurface of pillar body 51 disposed in engaging unit 21 is surrounded byclaws 22 and 23 and the R-surface portion between the side surfaces offame 20.

In the case that holder 50 is disposed in frame 20, four columnar bodies51 are fitted in four engaging units 21. Therefore, each pillar body 51is held between claws 22 and 23 of engaging unit 21. In other words, ineach pillar body 51, the side circumferential surface is gripped byclaws 22 and 23 of engaging unit 21. Pillar body 51 and engaging unit 21engage each other to fix pillar body 51 to frame 20, thereby attachingholder 50 to frame 20.

Each of claws 22 and 23 is caulked in pillar body 51 while each pillarbody 51 is fitted in engaging unit 21. For example, as indicted by anarrow in FIG. 5, first claw 22 d is pressed in engaging unit 21 dforward (a downward direction in FIG. 5) and second claw 23 d is pressedin engaging unit 21 d rightward (a rightward direction in FIG. 5). Claws22 and 23 invade in pillar body 51 by caulking claws 22 and 23, andpillar body 51 is strongly fixed to frame 20.

In the vibration generator in the background art, the vibrator issupported using the plate spring attached to the chassis. For example,in the vibration generator in which the plate spring is attached to thechassis using the screw, unfortunately the structure of the portion inwhich the plate spring is attached onto the chassis side becomescomplicated. Therefore, the assembly man-hour of the vibration generatorincreases, and the number of components also increases, which increasesthe production cost of the vibration generator. The problem becomes moreprominent with increasing demand for the downsizing and the low profileof the vibration generator. That is, because the downsizing of thecomponent advances with the downsizing of the vibration generator, it isnecessary to adopt attachment methods, such as the spot welding, insteadof the screw clamp or caulking, and the structure of the attachmentportion between the components becomes complicated. For example, in thecase that the spot welding is performed to the attachment portion of theplate spring and the chassis, the region where the spot welding isperformed becomes brittle against the impact force. Therefore, it isnecessary to perform the spot welding at many points in order tomaintain high reliability of the vibration generator, and sometimes ittakes a lot of trouble with the production. The problem with the methodfor joining the spring unit and the chassis is not originally generatedin the vibration generating device in the background art that has thestructure in which the spring unit and the flame are integrally molded.However, in this case, unfortunately the material used for the chassisis restricted to a material, which can be molded while being integralwith the spring unit.

On the other band, in the first embodiment holder 50 including pillarbody 51 is integrally molded, and pillar body 51 is fitted in engagingunit 21 to attach holder 50 to frame 20. Holder 50 can easily beattached to flame 20, and the number of components is suppressed to alow level, so that the production cost of vibration generator 1 can bereduced. Because each holder 50 and frame 20 is integrally formed, theattachment portion of holder 50 and frame 20 does not become brittle.Accordingly, the reliability of vibration generator 1 can be enhancedagainst the impact. It is not necessary to attach holder 50 to frame 20using other members, such as the screw, so that the downsizing, lowprofile, weight reduction of vibration generator 1 can be implemented.

In the structure of the background art in which the spring unitsupporting the vibrator and the chassis are integrally molded usingresin, unfortunately it is necessary that the spring unit and thechassis be made of the same material for the viewpoint of materialselection. However, in the first embodiment, the number of componentsdecreases because holder 50 and frame 20 are constructed by differentmembers. While holder 50 and frame 20 have the simple structures thatcan easily be assembled, the material for frame 20 can properly beselected. Accordingly, flame 20 can be configured to exert its functionwithout separately providing a member that acts as a magnetic circuit ora magnetic shield.

In holder 50, pillar body 51, arm 53, and vibrator retention unit 55 areintegrally molded using the elastic material. Accordingly, the number ofcomponents decreases, and holder 50 can easily be produced. In the firstembodiment, magnet 60 and yoke 70 are formed by the insert moldingtogether with holder 50. Accordingly, holder 50 can easily beconstructed while retaining vibrator 80, and a production process ofvibration generator 1 can be simplified.

Engaging unit 21 and frame 20 are integrally formed such that claws 22and 23 are formed while the notch is partially provided in the sidesurface of frame 20. Accordingly, the number of components can decreaseto reduce the production cost.

In the attachment structure of holder 50 to flame 20, columnar pillarbody 51 is gripped by two claws 22 and 23. Accordingly, while thestructure of vibration generator 1 is simplified, pillar body 51 issurely positioned in flame 20, and accuracy of the attachment of holder50 to frame 20 can be enhanced. Because of the structure in which claws22 and 23 are caulked with respect to pillar body 51, holder 50 isstrongly attached to frame 20.

The attachment structure of vibrator 80 to holder 50, namely, theattachment structure of magnet 60 and yoke 70 to holder 50 is notlimited to the insert molding. For example, magnet 60 and yoke 70, whichare joined to each other by the welding, may be assembled in and bondedto integrally-molded holder 50. Alternatively, holder 50 and yoke 70 maybe integrally molded and then magnet 60 may be attached to yoke 70.

[Structure of Yoke]

Vibrator 80 moves under the influence of the magnetic field, which isgenerated by the coil disposed below. Therefore, sometimes vibrator 80is displaced in the vertical direction or tilted from the horizontalplane (from this standpoint, the movement of vibrator 80 is not strictlyperformed within the horizontal plane However, a displacement amount oran attitude change amount in the vertical direction of vibrator 80 isrelatively small Therefore, hereinafter the movement of vibrator 80 ismacroscopically referred to as “vibrator 80 moves horizontally”). In thecase that a force is externally applied to vibration generator 1,sometimes vibrator 80 is vertically displaced with respect to frame 20.Vibration generator 1 has the low-profile structure, and a distancebetween frame 20 and the upper surface of vibrator 80 is relativelynarrow. Therefore, when vibrator 80 is vertically displaced or inclinedwith respect to frame 20, sometimes an upper portion of vibrator 80contacts the inner surface of the upper surface of frame 20.

In the first embodiment, projections 75 a and 75 b on the upper surfaceof yoke 70 are configured to abut on frame 20 when vibrator 80 isvertically displaced or inclined with respect to frame 20.

As illustrated in FIG. 1, projections 75 a and 75 b are provided toproject from the upper surface of yoke 70 toward the inner surface ofthe upper surface of frame 20. Projections 75 a and 75 b aresymmetrically provided with respect to a plane (a plane parallel to aZX-plane), which passes through the center of vibrator 80 and isperpendicular to the front-back direction that is the movement directionof vibrator 80. Projections 75 a and 75 b are located at two points onthe plane, which passes through the center of vibrator 80 and isparallel to a YZ-plane. That is, in the first embodiment, projection 75a is provided at the back of the central portion in the crosswisedirection of the upper surface of vibrator 80. Projection 75 b isprovided in front of the central portion in the crosswise direction ofthe upper surface of vibrator 80, and projection 75 b is provided so asto be symmetrical to projection 75 a.

FIG. 6 is a sectional view of yoke 70 taken on the line B-B of FIG. 1.

As illustrated in FIG. 6, in the first embodiment, each of projections75 a and 75 b has a curved shape that is convex upward (the rightdirection in FIG. 6). In other words, each of projections 75 a and 75 bhas the curved shape that is convex toward the inner surface of theupper surface of frame 20. For example, in each of projections 75 a and75 b, the surface shape is formed into a substantially spherical shape(a substantially arc shape in the cross section in FIG. 6). Each ofprojections 75 a and 75 b is formed such that projections 75 a and 75 bare extruded upward from plate-like yoke 70 by press working orsheet-metal working. That is, each of projections 75 a and 75 b and theremaining portion of yoke 70 are integrally formed. Each of projections75 a and 75 b is not limited to the structure in FIG. 6. For example,each of projections 75 a and 75 b may be provided such that a memberformed separately from the main body of yoke 70 is attached to the uppersurface of yoke 70. Each of projections 75 a and 75 b may be formed suchthat another liquid member (for example, an epoxy resin material or amelted metal) is put on the upper surface of yoke 70 and then cured orsolidified.

In the first embodiment, because projections 75 a and 75 b are providedon the upper surface of yoke 70, even if vibrator 80 comes close toframe 20, at first projection 75 a or projection 75 b contacts frame 20.An area that contacts frame 20 is restricted because the region thatcontacts frame 20 is restricted to projections 75 a and 75 b.Accordingly, when projections 75 a and 75 b of vibrator 80 contactsframe 20, a frictional force acting on vibrator 80 is reduced, and has alittle influence on the operation of vibrator 80. Properly operablevibration generator 1 can further be thinned. The frictional forceacting on vibrator 80 is reduced, so that power consumption of vibrationgenerator 1 can be reduced. The operation of vibrator 80 can beprevented from being obstructed due to the contact with flame 20, andvibrator 80 can smoothly be operated.

Projections 75 a and 756 are symmetrically disposed with respect to themovement direction (the vibration direction) of vibrator 80. Whenvibrator 80 contacts frame 20 during the vibration, projections 75 a and75 b contact surely frame 20 while remaining region hardly contactsframe 20. Accordingly, the influence of the contact with frame 20 on theoperation of vibrator 80 can surely be reduced.

Because each of projections 75 a and 75 b has the spherical shape thatis convex toward the inner surface of the upper surface of frame 20,each of projections 75 a and 75 b and frame 20 point-contact with eachother. Accordingly, the frictional force acting on vibrator 80 cansurely be reduced, and vibrator 80 can surely be operated.

Second Embodiment

Because a basic configuration of a vibration generator according to asecond embodiment is identical to that of the first embodiment, therepetitive description is omitted. The second embodiment differs mainlyfrom the first embodiment in that the vibrator includes a weight and aflexible printed board.

FIG. 7 is a plan view illustrating a vibration generator 201 of thesecond embodiment. FIG. 8 is a sectional view taken on a line E-E ofFIG. 7.

In FIG. 7, similarly to FIG. 1, a holder 250 and the like, which areoriginally hidden behind upper surface of frame 20, are partiallyillustrated by the solid line. A board 210 (illustrated in FIG. 8) isnot illustrated in FIG. 7.

The structure of vibration generator 1 differs mainly from that ofvibration generator 1 of the first embodiment in the following twopoints. That is, vibration generator 201 includes holder 250 instead ofholder 50, and includes board 210 instead of double-side board 10. Board210 has a structure different from that of double-side board 10.

As illustrated in FIG. 7, similarly to holder 50, holder 250 includesfour pillar bodies 51 and four arms 53. Holder 250 includes a vibratorretention unit (hereinafter sometimes referred to a retention unit) 255having a shape different from that of vibrator retention unit 55. Magnet60, weights 281 and 282, and a yoke 270 are attached to vibratorretention unit 255. That is, in the second embodiment, magnet 60,weights 281 and 282, and yoke 270 constitute a vibrator 280 of vibrationgenerator 201.

As illustrated in FIG. 8, board 210 is a flexible printed board (FPC)that is disposed so as to hold a bottom plate 230. In other words, board210 is disposed so as to partially cover double sides of bottom plate230. In the second embodiment, bottom plate 230 has a planar shape.Bottom plate 230 is fixed to frame 20 while fitted in a region on thebottom surface side of frame 20. A notch 235 is provided in end edgeportion (an example of the part of the rim portion) on the right side ofbottom plate 230. Therefore, the inside and the outside of vibrationgenerator 201 are communicated in the portion, in which notch 235 isprovided, while bottom plate 230 is fixed to fame 20.

Bottom plate 230 is made of nonmagnetic materials, such as nonmagneticstainless steel. Because vibration generator 201 is surrounded by fame20 and bottom plate 230, which are made of the metallic material,vibration generator 201 is easily handled and durability of vibrationgenerator 201 is also improved.

Board 210 includes an upper surface unit 216 that is disposed along theupper surface of bottom plate 230, a bottom surface unit 217 that isdisposed along the bottom surface of bottom plate 230. A folded-backunit 218 is formed between upper surface unit 216 and bottom surfaceunit 217. Upper surface unit 216 is disposed so as to be held betweencoil 40 and bottom plate 230. In folded-back unit 218 located in notch235, board 210 is folded back such that bottom surface unit 217 isprovided along the bottom surface of bottom plate 230. For example,board 210 is fixed to bottom plate 230 by bonding.

FIG. 9 is a perspective view illustrating holder 250. FIG. 10 is a planview illustrating holder 250.

In holder 250, similarly to FIG. 3, magnet 60, yoke 270, and weights 281and 282 are not illustrated in FIG. 9. Yoke 270 is not illustrated inFIG. 10.

As illustrated in FIG. 9, an aperture 255 a and apertures 2556 b and 255are provided in retention unit 255 of holder 250. Magnet 60 is attachedto aperture 255 a. Apertures 255 b and 255 c are provided on both sidesin the crosswise direction of aperture 255 a so as to overhang in thecrosswise direction from the region where aperture 255 a is provided.Each of apertures 255 b and 255 c has a rectangular shape, in which thefront-beck direction constitutes a long side, when viewed from above.Elastic materials are formed so as to be recessed from the upper surfaceof retention unit 255 in a region between aperture 255 a and aperture255 b and a region between aperture 255 a and aperture 255 c. Therefore,apertures 255 a, 255 b, and 255 c are partitioned from one another.

As illustrated in FIG. 10, weights 281 and 282 are attached to apertures255 b and 255 c, respectively. Holder 250 has a symmetrical shape withrespect to the plane, which passes through the central portion ofvibrator 280 and is perpendicular to the crosswise direction. That is,weights 281 and 282 have the same shape.

FIG. 11 is a development diagram illustrating board 210.

In board 210 in FIG. 11, upper surface unit 216, bottom surface unit217, and folded-beck unit 218 are developed into the planar shape. Asillustrated in FIG. 11, two pads 211 and 212 are provided in uppersurface unit 216 of board 210, and two pads 211 a and 212 a are providedin bottom surface unit 217. Pad 211 and pad 211 a are connected througha wiring pattern so as to become the same potential, and pad 212 and pad212 a are connected through a wiring pattern so as to become the samepotential. The winding end portion of coil 40 is connected to pads 211and 212 of upper surface unit 216. Pads 211 a and 212 a of bottomsurface unit 217 constitute an electrode in the case that vibrationgenerator 201 is mounted on the circuit.

As illustrated in FIG. 7, yoke 270 is one magnetic plate that is formedso as to cover the portion in which magnet 60 and weights 281 and 282are provided in the upper surface of vibrator 280. In the secondembodiment, holder 250, magnet 60, yoke 270, and weights 281 and 282 areintegrally molded by the insert molding. Therefore, vibrator 280 isretained by retention unit 255 of holder 250.

FIG. 12 is a plan view illustrating yoke 270. FIG. 13 is a sectionalview taken on a line F-F of FIG. 12.

As illustrated in FIG. 12, four projections 275 (275 a, 275 b, 275 c,and 275 d) are provided in yoke 270. As illustrated in FIG. 13, in thesecond embodiment, similarly to the first embodiment, each projection275 has the spherical shape that is convex toward the inner surface ofthe upper surface of frame 20 (upward, in the Z-direction).

Projections 275 are symmetrically disposed on yoke 270. That is, asillustrated in FIG. 7, projections 275 a and 275 b are located at twopoints, which are symmetrical to each other with respect to a it plane(a plan parallel to the ZX-plan). The first plane passes through thecenter of vibrator 280, and is perpendicular to the front-back directionthat is the movement direction of vibrator 280. Projections 275 a and275 b are located at two points on a second plane, which passes throughthe center of vibrator 280 and is parallel to a YZ-plane. On the otherhand, projections 275 c and 275 d are symmetrical to each other withrespect to the second plane, and provided at two points on the firstplane. That is, in the second embodiment, projection 275 a is providedat the back of the central portion in the crosswise direction of theupper surface of vibrator 280. Projection 275 b is provided in front ofthe central portion in the crosswise direction of the upper surface ofvibrator 280, and projection 275 b is provided so as to be symmetricalto projection 275 a. Projection 275 c is provided on the right side andin central portion in the front-back direction of the upper surface ofvibrator 280. Projection 275 d is provided on the left side and incentral portion in the front-back direction of the upper surface ofvibrator 280, and projection 275 d is provided so as to be symmetricalto projection 275 c.

In the second embodiment, because vibration generator 201 basically hasthe same configuration as vibration generator 1 of the first embodiment,the same effect as the first embodiment is obtained. In the secondembodiment, weights 281 and 282 are provided in vibrator 280, weights281 and 282 are displaced with the reciprocation of vibrator 280.Therefore, a vibration-force generation amount can be increased. Thenecessary vibration force can easily be adjusted irrespective of thesize or length of arm 53 and the elastic material. A metal having arelatively large specific weight may be used as weights 281 and 282.However, there is no limitation to the material for weights 281 and 282.

In the second embodiment, board 210 that is of an FPC is used.Accordingly, in board 210, the size in the vertical direction ofvibration generator 201 can be reduced compared with the use of thedouble-side board. The shape of bottom plate 230 can be simplified.

Because notch 235 is provided in bottom plate 230, board 210 does notrun over the outside of the chassis, but board 210 can surely beprotected.

In the second embodiment, because projections 275 are provided in yoke270, vibration generator 201 can be thinned while vibrator 280 movesproperly. In yoke 270, projections 275 e and 275 d are provided in thepositions corresponding to the crosswise direction in which weights 281and 282 are provided. Therefore, an inertia force increases by providingweights 281 and 282, and projections 2750 and 275 d contacts frame 20even in the structure in which vibrator 280 easily contacts flame 20.Accordingly, vibration generator 201 can surely be operated.

Because bottom plate 230 is made of the nonmagnetic material, similarlyto the first embodiment, the operation of vibrator 280 is not obstructedeven if the distance between vibrator 280 and bottom plate 230 isnarrow. Accordingly, the high-durability, low-profile vibrationgenerator 201 in which the bottom portion is covered with bottom plate230 can be provided.

Third Embodiment

Because a basic configuration of a vibration generator according to athird embodiment is identical to that of the first embodiment, therepetitive description is omitted. The third embodiment differs mainlyfrom the first and second embodiments in that plural coils are provided.

FIG. 14 is a plan view illustrating a vibration generator 401 accordingto a third embodiment. FIG. 15 is a sectional view taken on a line G-Gof FIG. 14.

In FIG. 14, similarly to FIG. 1, a holder 450 and the like, which areoriginally hidden behind upper surface of frame 20, are partiallyillustrated by the solid line. A structure in which four pillar bodies51 of holder 450 are retained by fame 20 is not illustrated in FIG. 14.In the third embodiment, the structure in which holder 450 is retainedby frame 20 is identical to that of the first embodiment.

A vibration generator 401 of the third embodiment differs from vibrationgenerator 1 of the first embodiment in that vibration generator 401includes holder 450 instead of holder 50 and that weights 481 to 484 areincluded in a vibrator 480. Vibration generator 401 differs fromvibration generator 201 of the second embodiment in that vibrationgenerator 401 includes two coils 440 a and 440 b. Vibration generator401 is configured to reciprocate vibrator 480 in the crosswise directionto generate the vibration.

As illustrated in FIG. 15, similarly to board 210 of the secondembodiment, a board 410 is a flexible printed board that is disposed soas to hold a bottom plate 430. Bottom plate 430 is made of nonmagneticmaterials, such as nonmagnetic stainless steel. Bottom plate 430 isconfigured similarly to bottom plate 230 of the second embodiment. Thatis, bottom plate 430 is fixed to frame 20 while fitted in a region onthe bottom surface side of frame 20. A notch 435 is provided in an endedge portion on the right side of bottom plate 430. An upper surfaceunit 416 of board 410 is disposed so as to be held between coils 440 aand 440 b and bottom plate 430. In a folded-back unit 418 located in anotch 435, board 410 is folded back such that a bottom surface unit 417is 16 provided along the bottom surface of bottom plate 430. Therefore,double sides of bottom plate 430 are partially covered with board 410.

FIG. 16 is a perspective view illustrating holder 450 and vibrator 480.FIG. 17 is an exploded perspective view of the holder and the vibratorof FIG. 16.

As illustrated in FIG. 16, similarly to holder 50, holder 450 includesfour pillar bodies 51 and four arms 53. In the third embodiment, eacharm 53 is formed such that the front-back direction is the lengthwisedirection. Therefore, vibrator 480 can vibrate in the crosswisedirection.

As illustrated in FIG. 17, holder 450 includes a vibrator retention unit(hereinafter sometimes referred to a retention unit) 455 having a shapedifferent from that of vibrator retention unit 55. A magnet 460 andweights 481 and 482 disposed on the right and left of magnet 460 areaccommodated in retention unit 455. A yoke 470 is attached to the uppersurface of retention unit 455. Yoke 470 is formed so as to overhang inthe front-back direction from retention unit 455. Weights 483 and 484are attached onto a lower side of the portion overhanging from retentionunit 455 in yoke 470. That is, in the third embodiment, magnet 460,weights 481, 482, 483, and 484, and yoke 470 constitute a vibrator 480of vibration generator 401. The members constituting vibrator 480 areintegrally formed as a whole by bonding, solvent welding, welding andinsert molding.

Holder 450 has a symmetrical shape with respect to a third plane (aplane parallel to the YZ-plane) and a fourth plane (a plane parallel tothe ZX-plane). The third plane passes through the central portion ofvibrator 480, and is perpendicular to the crosswise direction. Thefourth plane passes through the central portion of vibrator 480, and isperpendicular to the front-back direction. Weights 481 and 482 have thesame shape. Weights 483 and 484 have the same shape.

Yoke 470 is formed into a planar shape as a whole so as to cover thesubstantially whole upper surface of retention unit 455. As illustratedin FIG. 17, near both side portions in the crosswise direction of yoke470, apertures 471 a and 471 b are formed in the positions correspondingto weights 481 and 482. Protrusions 481 a and 482 a protruding upwardare formed on the upper surfaces of weights 481 and 482, respectively.Protrusions 481 a and 482 b are formed so as to be fitted in apertures471 a and 471 b, respectively. That is, weights 481 and 482 are fixed toyoke 470 while protrusions 481 a and 482 b are fitted in apertures 471 aand 471 b.

In the third embodiment, although the shape of magnet 460 issubstantially identical to that of magnet 60 of the first embodiment, amagnetization state of magnet 460 differs from that of magnet 60. Thatis, magnet 460 is magnetized in single pole. The bottom surface side ofmagnet 460 is magnetized in one of the S-pole and the N-pole.

In yoke 470, overhangs 473 a to 473 d are formed so as to extend in thevertical direction from the regions corresponding to four vertices ofmagnet 460. Overhang 473 a is provided at a left rear portion ofvibrator 480. Overhang 473 b is provided at a right rear portion ofvibrator 480. Overhang 473 c is provided at a left front portion ofvibrator 480. Overhang 473 d is provided at a right front portion ofvibrator 480. Overhangs 473 a to 473 d overhang forward or backward fromretention unit 455 when viewed from above. In weight 483, the uppersurfaces in crosswise direction of both the side portions are fixed toyoke 470 while joined to overhang 473 a and 473 b. In weight 484, theupper surfaces in the crosswise direction of both the side portions arefixed to yoke 470 while joined to overhang 473 c and 473 d. A raisedunit 483 a is formed on the upper surface of weight 483 so as to befitted between overhang 473 a and overhang 473 b. A raised unit 484 a isformed on the upper surface of weight 484 so as to be fitted betweenoverhang 473 c and overhang 473 d. Raised units 483 a and 484 a areraised from the upper surfaces of weights 483 and 484 by thesubstantially same level as a thickness of yoke 470. Therefore, theweight of vibrator 480 can be increased without increasing or enlargingthe size in the vertical direction of vibrator 480.

FIG. 18 is a development diagram illustrating board 410.

In board 410 in FIG. 18, upper surface unit 416, bottom surface unit417, and folded-back unit 418 are developed into the planar shape. InFIG. 18, each of the positions in which coils 440 a and 440 b aremounted is illustrated by a hold alternate long and two short dashesline.

Coils 440 a and 440 b are disposed so as to be adjacent to each other inthe crosswise direction, namely, the direction corresponding to themovement direction of vibrator 480. Coil 440 a is disposed on the leftside (the lower side in FIG. 18) of vibration generator 401, and coil440 b is disposed on the right side (the upper side in FIG. 18) ofvibration generator 401. As illustrated in FIG. 14, coils 440 a and 440b are symmetrically disposed with respect to the third plane.

As illustrated in FIG. 18, pads 411 a and 411 b and pads 412 a and 412 bare provided in upper surface unit 416 of board 410. Pad 411 a isprovided in the center of coil 440 a. Pad 411 b is provided in thecenter of coil 440 b. Each of pads 412 a and 412 b is disposed at theback of coils 440 a and 440 b. Pads 413 a and 413 b are provided inbottom surface unit 417 of board 410. Pad 411 a and pad 413 a areconnected through the wiring pattern so as to become the same potential.Pad 411 b and pad 413 b are connected through the wiring pattern so asto become the same potential. Pad 412 a and pad 412 b are connectedthrough the wiring pattern so as to become the same potential. Forexample, pads 412 a and 412 b are connected to a ground potential. Thewinding end portion of coil 440 a is connected to pads 411 a and 412 a.The winding end portion of coil 440 b is connected to pads 411 b and 412b. Pads 413 a and 413 b of bottom surface unit 417 constitute theelectrode in the case that vibration generator 401 is mounted on thecircuit.

Vibration generator 401 is driven such that the current having differentorientations are passed through pads 413 a and 413 b and coils 440 a and440 b. That is, because magnet 460 is magnetized in the single pole,vibrator 480 moves in the crosswise direction as coils 440 a and 440 balternately excited in different polarities.

As illustrated in FIG. 14, yoke 470 is one magnetic plate. In the thirdembodiment, projections 475 a, 475 b, 475 c, and 475 d are provided inyoke 470.

FIG. 19 is a plan view illustrating yoke 470. FIG. 20 is a sectionalview taken on a line H-H of FIG. 19.

As illustrated in FIG. 19, four projections 475 (475 a, 475 b, 475 c,and 475 d) are provided in yoke 470. Projection 475 a is provided inoverhang 473 a. Projection 475 b is provided in overhang 473 b.Projection 475 c is provided in overhang 473 c. Projection 475 d isprovided in overhang 4734. As illustrated in FIG. 20, in the thirdembodiment, similarly to the first embodiment, each projection 475 hasthe spherical shape that is convex toward the inner surface of the uppersurface of frame 20 (upward, in the Z-direction).

Projections 475 we symmetrically disposed on yoke 470. That is,projections 475 a and 475 b are provided at two points symmetrical withrespect to the third plane, which is perpendicular to the crosswisedirection that is the movement direction of vibrator 480. Similarly,projections 475 c and 4754 are provided at two points symmetrical withrespect to the third plane. Projection 475 a is symmetrical toprojection 475 c with respect to the fourth plane, and projection 475 bis symmetrical to projection 475 d with respect to the fourth plane.

In the third embodiment, because vibration generator 401 basically hasthe same configuration as vibration generator 201 of the secondembodiment, the same effect as the second embodiment is obtained. Thatis, the third embodiment is identical to the second embodiment in thatvibrator 480 includes weights 481 to 484 and that board 410 that is ofthe FPC is used. Accordingly, in board 410, the size in the verticaldirection of vibration generator 401 can be reduced compared with theuse of the double-side board. Because weights 481 to 484 are provided,the vibration-force generation amount can be increased, and thenecessary vibration force can easily be adjusted. A metal having arelatively large specific weight may be used as weights 481 to 484.However, there is no limitation to the material for weights 481 and 484.

In the third embodiment, vibrator 480 is driven by the simple structurein which coils 440 a and 440 b are used. In this case, vibrator 480 cansurely be moved to one of coils 440 a and 440 b. Vibrator 480 canefficiently be moved with a high driving force, so that performance ofvibration generator 401 can be enhanced.

Projections 475 are provided near the four corner portions of yoke 470,so that vibration generator 401 can be thinned while vibrator 480 movesproperly. Even if vibrator 480 takes any attitude, a contact rangebetween vibrator 480 and frame 20 can surely be reduced.

In the third embodiment, because bottom plate 430 is made of thenonmagnetic material, the operation of vibrator 480 is not obstructedeven if the distance between vibrator 480 and bottom plate 430 isnarrow. Accordingly, the high-durability, low-profile vibrationgenerator 401 can be provided.

Fourth Embodiment

Because a basic configuration of a vibration generator according to afourth embodiment is identical to that of the second embodiment, therepetitive description is omitted. The fourth embodiment differs mainlyfrom the first to third embodiments in the attachment structure of theholder to the frame.

FIG. 21 is a plan view illustrating a vibration generator 501 of thefourth embodiment. FIG. 22 is a sectional view taken on a line J-J ofFIG. 21.

In FIG. 21, similarly to FIG. 1, a holder 550 and the like, which areoriginally hidden behind upper surface of a frame 520, are partiallyillustrated by the solid line. A magnet and the like, which are retainedoriginally by holder 550, and a vibrator constructed by the magnet andthe like are not illustrated in FIGS. 21 and 22. A flexible printedboard and a coil disposed on the flexible printed board are also notillustrated. In the fourth embodiment, the structure of the componentthat is not illustrated is identical to that of the second embodiment.

Vibration generator 501 differs from vibration generator 201 of thesecond embodiment in the following points. That is, vibration generator501 includes holder 550 instead of holder 250. Vibration generator 501also includes frame 520 instead of frame 20. Vibration generator 501 issubstantially identical to vibration generator 201 in other structures.For example, magnet 60, weights 281 and 282, and yoke 270 are retainedin holder 550 in the same manner as holder 250. Vibration generator 501is configured to generate the vibration such that the vibratorconstructed in the same manner as the second embodiment is reciprocatedin the font-back direction.

In the fourth embodiment, the attachment structure of holder 550 toframe 520 is configured as follows. That is, as illustrated in FIG. 22,holder 550 includes four columnar bodies (an example of the fixed unit)551 (551 a, 551 b, 551 o, and 551 d). Each pillar body 551 is providedin the position corresponding to pillar body 51 of holder 250. Pillarbody 551 is fixed to frame 520 as described later, whereby holder 550 issupported by frame 520.

FIG. 23 is a plan view illustrating holder 550 of the fourth embodiment.

A hole unit 552 (552 a, 552 b, 552 c, and 552 d) is made in each pillarbody 551 of holder 550. As illustrated in FIG. 22, each hole unit 552 ismade so as to pierce pillar body 551 from the upper surface to the lowersurface. Each hole unit 552 is made such that the center of hole unit552 is located in the central portion of pillar body 551 when viewedfrom above. Each hole unit 552 has a cylindrical shape. Each hole unit552 is made such that the vertical direction perpendicular to themovement direction of the vibrator, namely, the front-back direction isthe depth direction. In other words, each hole unit 552 is made alongthe vertical direction, which is substantially perpendicular to theplate-shape vibrator disposed substantially horizontally.

FIG. 24 is a bottom view illustrating frame 520 of the fourthembodiment. FIG. 25 is a sectional view taken on a line K-K of FIG. 24.

As illustrated in FIG. 24, poles 521 (521 a, 521 b, 521 c, and 521 d),which are disposed at four corners when viewed from below, are providedin frame 520. Each of four poles 521 is a pin having a columnar shape.Poles 521 are disposed in the positions corresponding to four hole units552 of holder 550, respectively. As illustrated in FIG. 25, each pole521 is disposed such that the lengthwise direction is the verticaldirection, namely, the direction substantially perpendicular to themovement direction of the vibrator. Each pole 521 is vertically providedin frame 520 such that an upper end portion of each pole 521 projectsdownward while being press-fitted in a press fitting hole 522 (522 a,522 b, 522 c, and 522 d) made in a top surface (a portion constitutesthe lower side in FIG. 25) of the main body of frame 520. Each pole 521projects from the top surface of the main body of frame 520 by a lengthslightly shorter than the size in the vertical direction of pillar body551. Each pole 521 is made of metals, such as steel. However, pole 521is not limited to the metal. For example, pole 521 may be molded usingresin.

As illustrated in FIG. 22, holder 550 is attached to frame 520 such thatpoles 521 are fitted in hole units 552 from above. Bottom plate 230 isdisposed below holder 550 while holder 550 is disposed in frame 520.Therefore, holder 550 is retained in frame 520 so as not to drop outfrom pole 521. Holder 550 is attached to frame 520 while the magnet andthe like are previously attached to holder 550.

Each hole unit 552 has the cylindrical shape, and each pole 521 has thecolumnar shape. Because the attachment structure of holder 550, in whichpole 521 is inserted in hole unit 552, is adopted in the fourthembodiment, pillar body 551 is fixed to frame 520 while being rotatableabout a center axis of pole 521. In other words, when viewed from above,pillar body 551 is fixed to frame 520 such that the center axis of holeunit 552 is not displaced with respect to pole 521. Because pillar body551 is rotatable about pole 521, pillar body 551 rotates slightly aboutpole 521 when the vibrator is displaced in the front-beck direction.Therefore, the restoring force, which applied to the vibrator accordingto the displacement of the vibrator, can be decreased, and the vibrationcan efficiently and smoothly be generated.

In the fourth embodiment, holder 550 is attached to frame 520 such thatpillar body 551 is fitted in pole 521. Accordingly, unlike the first tothird embodiment, it is not necessary to provide the notch, whichretains pillar body 551, in the side surface of frame 520. It is notnecessary to provide the aperture in frame 520, so that vibrationgenerator 501 can be formed in a substantially sealed structuresurrounded by frame 520 and bottom plate 230. Accordingly, foreignsubstances, such as dust and dirt, can be prevented from invading invibration generator 501, and the reliability of vibration generator 501can be improved. Relatively complicated processes, such as a process ofcaulking pillar body 551, are not required, so that holder 550 caneasily be attached to frame 520 while hole unit 552 is fitted in pole521.

Additionally, vibration generator 501 has the same configuration asvibration generator 201 of the second embodiment. Accordingly, in thefourth embodiment, the same effect as the second embodiment is obtained.

In the fourth embodiment, the attachment structure of the pole to theframe is not limited to the press fitting. The pole may be attached tothe frame by a joining method in which the welding, the bonding or thescrew is used.

FIG. 26 is a bottom view illustrating a frame 620 used in a vibrationgenerator according to a first modification of the fourth embodiment.FIG. 27 is a side view of fame 620. FIG. 28 is a sectional view taken ona line L-L of FIG. 26.

A rear surface (backward surface) of frame 620 is illustrated in FIG. 27such that the downward direction in FIG. 27 is the upward direction (thepositive direction in the Z-axis) of frame 620. That is, FIG. 27 is aview when frame 620 is viewed from the same direction as FIG. 28.

As illustrated in FIG. 26, frame 620 includes four poles 621 (621 a, 621b, 621 c, and 621 d). Each pole 621 is disposed in the same position aspole 521 of frame 520. As illustrated in FIG. 27, a step 623 (623 a, 623b, 623 c, and 623 d) that is recessed downward by one step from otherportions is provided in the region where pole 621 is disposed in theupper surface (the lower-side portion in FIG. 27) of the main body offrame 620.

As illustrated in FIG. 28, a flange-shaped head 622 (622 a, 622 b, 622c, and 622 d) in which a diameter is larger than a diameter of the bodyportion of pole 621 is provided in an upper end portion of pole 621.Head 622 is configured such that a height in the vertical direction isless than a height of a step from the upper surface of frame 520 to theupper surface of step 623.

Each pole 621 is inserted from above in an aperture (not illustrated)formed in step 623, and pole 621 is attached to frame 620 such that head622 is hooked in step 623. Each pole 621 is fixed to frame 620 bywelding the surroundings of bead 622 to step 623. A size in which eachpole 621 projects downward can accurately be managed by providing head622, and therefore the vibration generator having the precise structurecan easily be produced.

Pole 621 is fixed to frame 620 by the welding, so that attachmentstrength of pole 621 to frame 620 can be improved. Accordingly, thedurability of the attachment structure of pole 621 can be improvedagainst the vibration. Step 623 is provided in frame 620, so that thewelded point can be prevented from projecting upward from the uppersurface of frame 620.

The vibration generator is configured while holder 550 is attached toframe 620. At this point, the vertical size of pillar body 551 may beset in consideration of the provision of step 623. Other components ofholder 550 may be configured in the same manner as the fourthembodiment.

Step 623 may be eliminated in frame 620. Head 622 may be eliminated inpole 621.

In the fourth embodiment, the hole unit made in the pillar body of theholder may be a bottomed hole. In this case, the pole provided in theframe may be configured to be shortened.

FIG. 29 is a side sectional view illustrating a configuration of avibration generator according to a second modification of the fourthembodiment.

The sectional view in FIG. 29 corresponds to the sectional view in FIG.22. Members, such as the flexible printed board and the coil, whichshould originally be provided in the vibration generator, are notillustrated in FIG. 29.

As illustrated in FIG. 29, a flame 625 of the vibration generatorincludes poles 626 b and 626 c that are short in the lengthwisedirection, namely, the vertical direction. Similarly to the main body offrame 620, step 623 is formed in the main body of frame 625. Similarlyto frame 620, frame 625 is constructed such that, after poles 626 b and626 c are inserted in the main body of frame 625, poles 626 b and 626 cand the main body of frame 625 are welded.

A holder 650 is attached to flame 625. Basically holder 650 has the sameconfiguration as holder 550. Holder 650 differs from holder 550 in thatholder 650 includes pillar bodies 651 b and 651 c in which bottomed holeunits 652 b and 652 c are formed.

In FIG. 29, only poles 626 b and 626 c are illustrated with respect topole 626, and only hole units 652 b and 652 c and columnar bodies 651 band 651 c are illustrated with respect to hole unit 652 and pillar body651. However, four poles 626, four pillar bodies 651, and four holeunits 652 are provided in frame 625 like vibration generator 501.

In the second modification, each hole unit 652 of holder 650 is closedby bottom 653 (for example, 653 b and 653 c) in the lower portion ofhole unit 652. Each hole unit 652 has the bottomed cylindrical shape, sothat holder 650 can easily be molded. That is, resin easily goes aroundthe whole of pillar body 651 during the molding of holder 650.Accordingly, what is called a shortage of resin going around can beprevented, and holder 650 can easily be molded. The effect to preventthe shortage of resin going around can surely be obtained by providing agate, into which the resin is poured, near each pillar body 651.

In the fourth embodiment, the attachment structure of the pole to themain body of the frame is not limited to the above way. For example, aflange abutting on the main body of the flame may be provided in eachpole.

FIG. 30 is a side sectional view illustrating a frame 525 used in avibration generator according to a third modification of the fourthembodiment.

The sectional view in FIG. 30 corresponds to the sectional view in FIG.25.

As illustrated in FIG. 30, the basic configuration of flame 525 isidentical to that of frame 520. Frame 525 differs from frame 520 in thattame 525 includes a pole 526 (526 a and 526 d) in which flange 527 (527a and 527 d) is formed. In FIG. 30, only poles 526 a and 526 d and onlyflanges 527 a and 527 d are illustrated with respect to pole 526 andflange 527. However, similarly to vibration generator 501, four poles526 and four flanges 527 are provided.

Flange 527 is formed in the position that is slightly recessed by thethickness of the main body of flame 525 from the upper end portion ofpole 526. Flange 527 has a diameter slightly larger than a diameter ofthe body portion of pole 526.

Flange 527 is press-fitted in press fitting hole 522 from the inside offrame 525 until flange 527 abuts on the top surface of the main body offrame 525. The distance from the top surface of the main body of frame525 to the lower and portion of pole 526 can easily be managed byforming flange 527 in pole 526, and the vibration generator can easilybe assembled with high accuracy.

FIG. 31 is a plan view illustrating a configuration of a vibrationgenerator 301 according to a fourth modification of the fourthembodiment FIG. 32 is a side sectional view of vibration generator 301of the fourth modification. FIG. 33 is a bottom view of vibrationgenerator 301 of the fourth modification.

The sectional view in FIG. 32 corresponds to the sectional view in FIG.22. A cross section passing through the substantial center in thecrosswise direction of vibration generator 301 is illustrated in FIG.32.

In FIG. 31, similarly to FIG. 1, a holder 350 and the like, which areoriginally bidden behind upper surface of frame 520, are partiallyillustrated by the solid line. The flexible printed board is notillustrated in FIG. 31. Bottom plate 230 and the like are notillustrated in FIG. 33. In the fourth modification, the structure of thecomponent that is not illustrated is identical to that of the firstembodiment.

Vibration generator 301 includes a holder 350 in which the shape isdifferent from that of holder 550 of vibration generator 501. Holder 350is attached to frame 520, which is constructed similarly to vibrationgenerator 501. That is, holder 350 is attached to frame 520 so as to befitted in pole 521. Holder 350 is configured such that the movementdirection of vibrator 380 is the crosswise direction (the X-axisdirection in FIG. 31).

Holder 350 includes a pillar body 351 (351 a, 351 b, 351 c, ad 351 d)that is disposed in the position corresponding to pole 521, a vibrator380, and an arm 353 (353 a, 353 b, 353 c, and 353 d) that connectsvibrator 380 and pillar body 351. In holder 350, these units areintegrally molded using resin.

A hole unit 352 (352 a, 352 b, 352 c, and 352 d) is made in pillar body351. For example, hole unit 352 is made in the same manner as hole unit552. The outer circumference surface of pillar body 351 is formed so asto contact the inner circumference surface of frame 520 in the state inwhich holder 350 is attached to frame 520. That is, pillar body 351 isformed into the shape corresponding to an R-curved surface of the cornerportion and planar portions located on both sides of the R-curvedsurface in the inner circumference surface. Therefore, pillar body 351contacts the inner circumference surface of frame 520 in a relativelywide range while holder 350 is attached to frame 520. Accordingly,pillar body 351 is surely retained such that the position and attitudeof pillar body 351 do not change with respect to frame 520. Becausepillar body 351 contacts frame 520 in the wide range, the vibrationgenerated by the movement of vibrator 380 easily propagates from holder350 to frame 520. Accordingly, the vibration can efficiently betransmitted to the outside of vibration generator 301.

Vibrator 380 includes magnet 60, a yoke 370, and a weight 381. Weight381 is formed so as to surround the side portion of magnet 60. Yoke 370is attached to the upper surfaces of magnet 60 and weight 381. Yoke 370includes apertures 371 a and 371 b that are formed on both sides in thecrosswise direction of yoke 370. Protrusions 381, each of which areformed in the upper surface of weight 381 so as to project upward, arefitted in apertures 371 a and 371 b.

Each arm 353 is formed such that the front-back direction is thelengthwise direction. That is, arms 353 a and 353 b am provided betweenthe right end portion of vibrator 380 and columnar bodies 351 a and 351b. On the other hand, arms 353 c and 353 d are provided between the leftend portion of vibrator 380 and columnar bodies 351 c and 351 d. Asillustrated in FIG. 33, the right and left side portions of weight 381are retained by retention units 355 made of resin. Retention units 355are formed so as to sandwich the side portion of weight 381 therebetweenin the front-back direction. Each arm 353 is connected to retention unit355 in the portion on the side of vibrator 380.

Fi. 34 is a view illustrating a configuration of holder 350 in vibrationgenerator 301 of the fourth modification.

In FIG. 34, the portion of one arm 353 c is enlarged in the bottom viewof vibration generator 301.

In holder 350 in a natural state (for example, a state in which holder350 is not attached to frame 520), the distance between pillar body 351a and pillar body 351 b is shorter than the distance between center axesof pole 521 a and pole 521 b. In the natural state, a distance betweenpillar body 351 c and pillar body 351 d is shorter than the distancebetween the center axes of pole 521 c and pole 521 d. Therefore, asindicated by an arrow Q in FIG. 34, when holder 350 is attached to frame520, each arm 353 is slightly lengthened in the lengthwise directioncompared with the natural state. That is, in the state in which holder350 is attached to flame 520, each arm 353 is elastically deformed fromthe natural state.

Because each arm 353 is attached while elastically deformed from thenatural state, a tension is applied to holder 350 by the restoring forceof arm 353. That is, vibration generator 301 has no play. In otherwords, when the magnetic attractive force acts on vibrator 380,vibration generator 301 can quickly generate the vibration as vibrator380 is displaced, and a responsive property of the vibration generationis enhanced.

Fifth Embodiment

Because a basic configuration of a vibration generator according to afifth embodiment is identical to that of the third embodiment, therepetitive description is omitted. The fifth embodiment differs from theabove embodiments in a structure of the arm of the holder.

FIG. 35 is a plan view illustrating a vibration generator 701 of thefifth embodiment. FIG. 36 is an exploded perspective view illustrating aholder 750 and vibrator 480 of vibration generator 701.

In FIG. 35, similarly to FIG. 1, holder 750 and the like, which areoriginally hidden behind upper surface of frame 20, are partiallyillustrated by the solid line. A flexible printed board and a coildisposed on the flexible printed board are also not illustrated in FIG.35. In the fifth embodiment, the structure of the component that is notillustrated is identical to that of the third embodiment. For example,the structure in which holder 750 is retained by frame 20 is identicalto that of the first embodiment.

Vibration generator 701 includes holder 750 in which the configurationis partially different from that of holder 450. In holder 750, vibrator480 is provided in vibrator retention unit 455. Vibrator 480 isconstructed while magnet 460, yoke 470, and weights 481 to 484 areretained in vibrator 480. Four columnar bodies 51 of holder 750 areretained in frame 20, whereby holder 750 is attached to frame 20. Holder750 is identical to holder 450 of the third embodiment in this point.That is, in vibration generator 701 in FIG. 35, the two coils (notillustrated) are excited to reciprocate vibrator 480 in the crosswisedirection, thereby generating the vibration.

As illustrated in FIG. 36, in the fifth embodiment, slits 754 (754 a,754 b, 754 c, and 754 d) are formed in four arms 53 of holder 750,respectively. Each slit 754 is formed along the lengthwise direction ofarm 53. That is, each slit 754 is formed such that the font-backdirection is the lengthwise direction. Four slits 754 have the sameshape.

As illustrated in FIG. 35, each slit 754 is formed in the centralportion of the width direction of arm 53 when viewed from above. Eachslit 754 is formed such that one of vertical end portions of each slit754 comes close to pillar body 51 while the other end portion comesclose to retention unit 455 (in the fifth embodiment, in retention unit455, the region retaining weights 471 a and 471 b). That is, each slit754 is formed in the substantially whole domain in the lengthwisedirection of arm 53. Each slit 754 pierces arm 53 from the upper surfaceto the lower surface. Therefore, it is said that each arm 53 is dividedinto right and left beam-shaped regions with slit 754 interposed betweenthe regions.

For example, slit 754 may be formed as follows. That is, when holder 750is integrally molded, arm 53 having slit 754 may be molded during moldrelease of holder 750 using a die having the shape for forming slit 754.After holder 750 is integrally molded, arm 53 in which slit 754 is notformed yet is machined in order to form slit 754.

Because vibration generator 701 roughly has the same configuration asvibration generator 401, basically the same effect as the thirdembodiment is obtained. In the fifth embodiment, the following effect isfurther obtained by forming slit 754 in arm 53.

That is, in the case of the same displacement amount of vibrator 480,compared with the case that slit 754 is not provided in arm 53, eachportion of arm 53 is more evenly deformed when slit 754 is provided inarm 53. Accordingly, arm 53 is hardly broken, and a life of holder 750is lengthened.

A vibration property of vibration generator 701 can easily be changed bychanging the shape and the position of slit 754. For example, avibration amount of vibrator 480 can easily be changed by changing awidth of slit 754. In other words, in the fifth embodiment, the width ofslit 754 may be set according to the desired vibration property.

The shape of slit 754 is not limited to the example in FIGS. 35 and 36.For example, slit 754 has the width of substantial zero, and only a cutmay be formed in arm 53.

In the fifth embodiment, a reinforcing plate may be inserted in theslit.

FIG. 37 is a plan view illustrating a vibration generator 801 accordingto a first modification of the fifth embodiment.

Similarly to FIG. 35, illustrations of components are partially omittedin FIG. 37. Similarly to holder 750, a holder 850 in which a slit 854(854 a, 854 b, 854 c, and 854 d) is formed in each arm 53 is provided invibration generator 801 of the first modification. Holder 850 includesfour reinforcing plates 859 (859 a, 859 b, 859 c, and 859 d). Invibration generator 801, other configurations are identical to those ofvibration generator 701 of the fifth embodiment.

FIG. 38 is a perspective view illustrating holder 850 and vibrator 480of vibration generator 801. FIG. 39 is an exploded perspective viewillustrating holder 850 and vibrator 480.

As illustrated in FIG. 38, each reinforcing plate 859 is disposed so asto correspond to pillar body 51 and arm 53 of holder 850. Eachreinforcing plate 859 includes a support unit 857 (857 a, 857 b, 857 c,and 857 d) and an insertion unit 858 (858 a, 858 b, 858 o, and 858 d).

As illustrated in FIG. 39, support unit 857 has a circular plate shapein which a diameter is slightly smaller than a diameter of each pillarbody 51. Support unit 857 is not limited to the circular shape. Supportunit 857 is not limited to the plate shape.

Insertion unit 858 has a substantially rectangular plate shape.Insertion unit 858 is partially connected to support unit 857. In thefirst modification, reinforcing plate 859 is formed such that insertionunit 858 and support unit 857 are punched out from one metallic sheetand such that insertion unit 858 is bent by 90 degrees with respect tosupport unit 857. Insertion unit 858 has such the thickness and the sizethat insertion unit 858 can be inserted in slit 854 previously formed inarm 53 of holder 850.

FIG. 40 is an enlarged view illustrating a portion in which reinforcingplate 859 of holder 850 is disposed. FIG. 41 is a side view of holder850.

FIG. 41 illustrates the left side of holder 850.

As illustrated in FIG. 40, reinforcing plate 859 is used while attachedto holder 850. Reinforcing plate 859 is attached to holder 850 such thatinsertion unit 858 is inserted in slit 854 and such that support unit857 is disposed on the upper surface of pillar body 51. As illustratedin FIG. 41, insertion unit 858 is formed such that the size in thevertical direction of insertion unit 858 is slightly larger than thesize in the vertical direction of arm 53. Insertion unit 858 is disposedin slit 854 so as to run over upward and downward from arm 53 by aalight amount.

As illustrated in FIG. 40, unlike slit 754 of holder 750, slit 854 isformed to the position in which slit 854 slightly invades in pillar body51. Insertion unit 858 is inserted in slit 854 such that the and edgeportion on the side of pillar body 51 invades in pillar body 51. Thatis, the end edge portion on the side of pillar body 51 of insertion unit858 is disposed in the position that is not largely deformed during themovement of vibrator 480.

Slit 854 is formed longer to the position closer to vibrator 480 beyondthe position of the end edge portion (the upper end edge portion in FIG.40) on the side of vibrator 480 of insertion unit 858. That is, the endedge portion on the side of vibrator 480 of insertion unit 858 isslightly separated from the end edge portion on the side of vibrator 480of slit 854 with a gap 854s intervened therebetween.

A circular hole is made in the central portion of support unit 857. Forexample, the hole is required in the following case. That is, like thefourth embodiment, sometimes the pillar body is fixed to the frame suchthat the pole on the frame side is fitted in the pillar body of theholder. In this case, when reinforcing plate 859 is arranged,reinforcing plate 859 is disposed such that the pole is inserted in thehole of support unit 857. In other cases (for example, the case thatreinforcing plate 859 is used while attached to holder 850), the hole insupport unit 857 may be eliminated.

In the fifth embodiment, reinforcing plate 859 is bent together with arm53 as retention unit 455 is displaced with respect to pillar body 51during the movement of vibrator 480. Insertion unit 858 is disposed likea cantilever because one end portion of insertion unit 858 is retainedby pillar body 51. Accordingly, when retention unit 455 is displaced inthe crosswise direction, each insertion unit 858 is bent such that theend portion on the side of vibrator 480 is most displaced in thecrosswise direction.

At this point, gap 854s is provided between insertion unit 858 and slit854. Accordngly, even if both insertion unit 858 and arm 53 are bent asretention unit 455 is displaced, insertion unit 858 does not stronglycontact the end edge portion of slit 854. Accordingly, generation of afailure such that insertion unit 858 invades in slit 854 to break arm 53is prevented.

According to the first modification, vibrator 480 can be retained whileslit insertion unit 858 is inserted in slit 854. The stiffness andstrength of arm 53 in which slit 854 is provided decrease compared withthe case that slit 854 is not formed. By inserting insertion unit 858having the proper thickness and size in slit 854, the stiffness of arm53 is properly maintained and the displacement amount of vibrator 480can be set so as to become proper. The bending of arm 53 due to gravityor the impact, which applied to vibrator 480, can be prevented whenvibration generator 801 is not driven.

Reinforcing plate is not limited to one in which the vertical positionis fixed by sandwiching support unit 857 between pillar body 51 and thetop surface of frame 20. Reinforcing plate may be fixed to pillar body51 by another method. Reinforcing plate may be fixed to frame 20 orbottom plate 230 separately from the pillar body.

In the fifth embodiment, the holder having the structure in which thearm is molded using plural resins may be used instead of the structurein which the slit is provided in the arm.

FIG. 42 is a plan view illustrating a holder 950 of a vibrationgenerator according to a second modification of the fifth embodiment.

In the second modification, the vibration generator includes holder 950instead of holder 750. In the vibration generator, other configurationsexcept holder 950 are identical to those of the fifth embodiment.

In the second modification, holder 50 and vibrator 480, which includesmagnet 460 and yoke 470, are integrally molded. For the sake ofconvenience, holder 950 in which vibrator 480 is not attached toretention unit 455 is illustrated in FIG. 42. That is, vibrator 480 isnot illustrated in FIG. 42, but only holder 950 made of the elasticmaterial is illustrated.

As illustrated in FIG. 42, similarly to holder 750, holder 950 includesretention unit 455 and four pillar bodies 51. In holder 950, retentionunit 455 and each pillar body 51 include an arm 953 (953 a, 953 b, 953c, and 953 d) in which the configuration is different from that ofholder 750.

In the second modification, each arm 953 is formed by two-color molding.In FIG. 42, the portion formed by the two-color molding is indicated byhatching.

FIG. 43 is a sectional view taken on a line M-M of FIG. 42.

As illustrated in FIG. 43, arm 953 is formed by the two-color moldingusing a first resin 954 a and a second resin 954 b. For example,retention unit 455, pillar body 51, and arm 953 are integrally formedusing first resin 954 a. Second resin 954 b is lower than first resin954 a In hardness.

Arm 953 is formed while the outside of the portion made of first resin954 a is covered with second resin 954 b. In other words, in the secondmodification, each arm 953 includes a core portion made of first resin954 a. The outside of the core portion is coated with second resin 954b.

First resin 954 a having the relatively high hardness is used as thematerial for the inside of each arm 953. Accordingly, the stiffness andthe strength of each arm 953 are ensured, and the core portion of arm953 becomes sound. The surroundings of first resin 954 a is covered withrelatively soft second resin 954 b. Therefore, a crack or a flaw ishardly generated in arm 953. Accordingly, the life of arm 953 can belengthened, and the reliability of the vibration generator can beimproved,

The disposition of the resin in each arm 953 is not limited to thesecond modification. For example, depending on the shape of holder 950,the relatively soft resin is disposed at the point on which a stress isconcentrated, which allows the life of arm 953 to be lengthened.

[Others]

The vibration generator may be configured by properly combining thefeature points of the above embodiments and modifications. For example,in the 26 vibration generators of the second to fifth embodiments, likethe first embodiment, double-side boards, such as a glass epoxy board,may be used instead of the flexible printed board. The production costof the vibration generator can be reduced in the case that thedouble-side board is used.

In the second to fifth embodiments, an R-chamfering unit may be providedin the notch of the bottom plate. For example, the R-chamfering unit maybe provided in the edge portion that is formed by forming the notch.Therefore, even if the board that is of the FPC is folded at the notch,the stress is hardly applied to the board, and the breakage of the boardcan more surely be prevented.

The material for the frame is not limited to the steel, but the framemay be made of another material. For example, the frame may be made ofresin separately from the holder. The frame may be formed such that theholder is surrounded by the frame without providing the upper surface orthe bottom surface when viewed from above. The frame may be formed intoa square shape when viewed from above.

The circuit board may not be provided. The bottom plate does not coverthe whole surface of the bottom portion of the frame, but the bottomplate may be disposed only in a part of the bottom portion of the fame.

Four projections may be provided in the yoke, or odd-numberedprojections may be provided in the yoke. The surface of the projectionis not limited to the spherical shape, and not limited to thecurved-surface shape. The projection is formed such that the regionhaving the restricted area contacts the inner surface of the frame.Therefore, the above effects can be obtained.

It is only necessary to provide at least two pillar bodies and at leasttwo arms. The pillar body is not limited to the columnar shape, but thepillar body may be formed into a polygonal column shape. The holder isnot limited to the integral molding, but the holder may be constructedby assembling plural members.

The attachment structure of the holder to the frame is not limited tothe structure in which two claws engage the pillar body or the structurein which the pole is fitted in the hole unit of the pillar body. In theattachment structure of the holder to the fame, the fixed unit havinganother shape on the holder side may engage engaging unit formed in theframe. For example, a hole-shape engaging unit is formed in the frame,and the projection on the holder side may be fitted in the engaging unitto attach the holder to the frame.

The holder is not limited to one that formed by single-color molding.For example, the pillar body, the retention unit, and the arm may beintegrally molded by the two-color molding using different materials.

The attachment structure of the vibrator to the holder, namely, theattachment structure of the magnet and the yoke to the holder is notlimited to the insert molding. For example, the magnet and the yoke,which are joined to each other by the welding, may be assembled in andbonded to the integrally-molded holder in a process different from theprocess of molding the holder. Alternatively, the holder and the yokemay be integrally molded and then the magnet may be attached to theyoke.

The weight may be disposed in the central portion of the magnet. In themagnet, the weight may be disposed in the portion that hardly influencesthe generation of the force moving the vibrator. Therefore, thevibration generator in which the large vibration force is generatedwhile the downsizing of the vibrator is implemented can be constructed.

Alternatively, the coil is attached to a main board of the device inwhich the vibration is used, and the frame to which the holder isattached is attached to the coil-mounted main board, whereby thevibration generator in which the vibrator is driven may be constructed.In other words, the vibration generator may be constructed using thecoil mounted on the board of another device.

The configuration of the holder is not limited to the holder used invibration generator, but the configuration can widely be applied. Thatis, the holder is configured such that a movable body (in theembodiments, the portion constituting the vibrator) provided in themagnet can be displaced through the arm with respect to the portionsupported by the frame. The holder can be used in various devices, suchas an actuator driven by the magnetic force and a device in which themovable body is used while properly displaced in a predeterminedorientation. In a device different from the vibration generator, thesame effect can be obtained by constructing the holder in the abovemanner. For example, by providing the projection in the yoke of theholder, the region where the movable body contacts the frame can berestricted, and the device can properly be operated.

It should be understood that the embodiments described above weillustrative and non-restrictive in every respect. The scope of thepreset invention is defined by the terms of the claims, rather than thedescription above, and is intended to include any modifications withinthe scope and meaning equivalent to the terms of the claims.

What is claimed is:
 1. A vibration generator comprising: a frame, aholder, and a magnet supported by the holder so as to be displaceablewith respect to the frame, wherein the holder includes a first aperture,a second aperture, and a third aperture, the first aperture, the secondaperture, and the third aperture are arranged in a displacementdirection of the magnet, the first aperture is arranged between thesecond aperture and the third aperture in the displacement direction ofthe magnet, the magnet is arranged in the first aperture, and weightsare arranged in the second aperture and the third aperture.
 2. Thevibration generator according to claim 1, wherein the weights are formedwith a metallic material.
 3. The vibration generator according to claim1, comprising a planar coil, wherein current is passed through theplanar coil to displace the magnet with respect to the frame.
 4. Thevibration generator according to claim 3, wherein the planar coilincludes a plurality of planar coils.